TDRD9 and Azoospermia: Although increasing numbers of genes associated with NOA have been reported through case reports and mouse model studies, the molecular basis of NOA is still poorly understood.[4] Only a small number of genes associated with azoospermia proposed by mouse models have been identified in humans, such as testis expressed 11 (TEX11), tudor domain containing 9 (TDRD9), Zinc finger MYND-type containing 15 (ZMYND15), and TATA-box binding protein associated factor 4b (TAF4B).[5]